Uncovering the mystery of white ink

I began my Tuesday with the best of intentions. I had spent the previous afternoon carving away tiny areas in my most recent linocut. There is always this sense of excitement and expectation when I print the next layer — as it is hard to predict the effects of the carving and the new color.

In my latest linocut, I needed to transition from a very bright yellow-green to blues, and I knew from experience that unless some of the green was blocked by a more opaque ink, I would not get to the blues that I sought. So I had printed a white ink, tinted with blue.

Titanium white

Was the culprit the Titanium White?

Alas, when I gently touched the surface of the linocut, I could feel that it was still tacky and wet. A bit of the very light blue remained on my finger. Sometimes the last layers of a linocut dry more slowly…but in this case I think the culprit was the Titanium White ink. With no printing happening on this day, I decided to try and discover why it was that the white ink behaved so differently from my other inks.

Sadly, when I typed in a search of “why does white ink not dry like other inks” I didn’t get any useful information. Complex treatises from the commercial printing industry surfaced, with discussions about squirting inks and plasticity. Not what I needed.

I was using Gambin’s Titanium White ink, which is a combination of titanium dioxide with a small amount of zinc oxide added in. Titanium white is the most reflective of pigments, reflecting 97.5% of the available light.

My search led me to learn more about the history of white pigment in art. Lead white is one of the oldest pigments, but is highly controlled now because of its toxicity. It was reputed to make Whistler ill when painting Symphony in White no. 1 (The White Girl). Yet despite its health consequences, painters continued to use it, even when zinc oxide was presented as an alternative in the middle of the 18th century. Zinc oxide had a difficult debut because it was four times as expensive as the lead white, and becameĀ brittle when dry.

Light blue covers green

Lots of titanium white plus a little ultramarine helps to cover a very strong yellow-green.

Titanium was identified as an element in 1795, but it wasn’t until the 1920s that a manufacturing process was developed to rid it of its iron impurities. When used in oil paints, titanium developed a spongy quality when dry that was not suitable for painting. When mixed with some of the more brittle zinc white, however, it was an acceptable and much less toxic alternative.

Creating pigments must be such a challenging job. Not only must the chemist think about how the product behaves now, she must also forecast how the artwork will age. In many media, this pigment is tenuously adhered to a substrate — whether a canvas or cotton rag paper. I can only guess that the ink makers felt it was better to have a slower drying and more pliable ink for my unstable paper. I may be completely mistaken, but this is my best guess for the day.

Perhaps tomorrow will bring a drier surface and I can indulge my curiosity by printing the next layer of ink.

The history of pigment is a fascinating one. These resources make for the perfect distraction while waiting for your pigment to dry:
Pigments through the ages
By Victoria Finlay: Color (2002) and The Brilliant History of Color (2014)

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